Endless track construction



Och 6 A. E. RIXMANN ETAL 3,347,602

ENDLESS TRACK CONSTRUCTION 3 Sheets-Sheet 1 Filed Oct. 28, 1965 L /zeyelzz ors:

17, 1957 A. E. RIXMANN ETAL 3,347,602

ENDLESS TRACK CONSTRUCTION 3 Sheets-Sheet 2 Filed Oct. 28, 1965 96L 1967 A. E. RIXMANN ETAL 3,347,602

ENDLESS TRACK CONSTRUCTION Filed Oct. 28, 1965 3 Sheets-Sheet 5 FORWARD M kjrwe Mm MA M United States Patent 3,347,602 ENDLESS TRACK CONSTRUCTION Amos E. Rixmann, 2315 NW. 56th St., Oklahoma City, Okla. 73112, and Lyman E. Knapp, Rte. 1, Box 140, Blackwell, Okla. 74631 Filed Oct. 28, 1965, Ser. No. 505,539 2 Claims. (Cl. 305-54) ABSTRACT OF THE DISCLOSURE Track shoes for an endless crawler type vehicle pivotally linked together and constructed in a manner to enable the shoes to have relative angular pivoting in both up and down directions.

This invention relates generally to endless track constructions for a crawler tractor, and more specifically to a novel track construction for a crawler tractor of the general type wherein the lower flight of the track between the driving sprocket and the front idler wheel is permitted to assume positions lying on either concave or convex curves.

The primary object of the present invention is to provide a novel endless track construction for crawler tractors of the type wherein the track is permitted to hex upwardly and downwardly between the rear driving sprocket and the front idler wheel, which will have long life and a minimum of service requirements.

It is a further object to provide a novel track arrangement in a construction of the preceding paragraph in which substantially no earth will work vertically through the track to the inside surfaces thereof.

It is a further object to provide a novel track arrangement according to the preceding paragraphs in which the surface of the track presents a substantially closed surface to the earth over which the track is moved.

It is a further object to provide a novel lubricant sealing arrangement in track constructions of the preceding paragraphs.

It is still another object to provide a novel track arrangement in constructions according to the preceding paragraphs in which the action or movement of the track in operation is such that the grousers enter and leave the earth upon which the track is moved with a minimum of casting or horizontal movement of the earth upon which the track is moved.

A novel feature of the invention in constructions according to the preceding paragraph is the construction which permits a substantial reverse bend at each link connection.

A further novel feature of the invention is the particular overlap arrangement of the track shoes which permits both forward and reverse bends of the track without the passage of earth through the track to the inside surfaces thereof.

A further novel feature of the invention is the provision in constructions according to the pre ceding paragraphs of a short riser on each side of each shoe to prevent earth from coming over the sides of the shoes.

A further unique feature of the present invention is the arrangement in constructions according to the preceding paragraphs in which the grouser on each shoe is positioned midway between the axes of the pins securing the links together to provide excellent penetration and removal of the grouser during movement of the track over the earth with a minimum of disturbance of the earth beneath the track.

Still another novel feature of the present invention is the arrangement of the various parts so that a minimum of vibration of the track occurs during the operation of a tractor having the subject track arrangement.

Other objects and features of the invention will be apparent upon a persual of the following specification and drawings in which:

FIGURE 1 is a perspective view of a crawler tractor of the type for which the present invention is intended;

FIGURE 2 is a top plan view of two link and shoe arrangements according to the invention;

FIGURE 3 is a side elevational view of a portion of the lower flight of a crawler track constructed according to the invention;

FIGURE 4 is a cross sectional view of the structure shown in FIGURE 2 and taken substantially along the line 4-4 of FIGURE 2;

FIGURE 5 is a cross sectional view of the structure shown in FIGURE 2 but with the track shoe omitted and taken substantially along the line 5-5 of FIGURE FIGURE 6 is an enlarged view of a portion of .the structure shown in FIGURE 5.

The present embodiment is the preferred embodiment, but it is to be understood that changes can be made in the present embodiment by one skilled in the art without departing from the spirit and scope of the present invention.

Generally, the present invention comprises a novel construction for an endless track for a tractor of the type as generally shown in FIGURE 1. Such a tractor permits the crawler track in both the upper and lower flights thereof between the front idler wheels and the rear driving sprockets to oscillate upwardly and downwardly. Such a crawler tractor is quite different from those generally presently known in the art wherein the tractor is provided with a track frame which, between the axis of the front idler wheel and the axis of the rear driving sprocket, is a straight and rigid frame with track rollers carried on that frame substantially preventing any upward or downward oscillations of the intermediate portions of the track. In the tractor shown in FIGURE 1, the front idler wheel and the wheel immediately. behind it are mounted on a rigid strut which is pivotally carried at its center so that those two wheels can oscillate upwardly and downwardly about a horizontal axis positioned transversely of the tractor. A similar construction is provided between the rear driving sprocket and the wheel immediately thereahead. With such a construction the intermediate portions of the tracks will bow upwardly when the crawler tractor passes over an obstruction such as shown in FIGURE 1. V

For any such tractor the desirability of a reasonable track life is well known. It is a further desirable feature that an endless track be constructed so that excessive vibration will not occur. Further, the track shoes of the crawler track should only minimally disturb the earth upon which the track travels. In a reduction to practice of the present invention it has been found that the track construction of the present invention provides long track life, excellent ground penetration with little disturbance of the ground, no working of earth upwardly through the lower track flight, and a minimum of vibration.

Referring to the drawings, a tractor 10 of FIGURE 1 is representative of the type for which the subject track invention is ideally suited. The endless track construction of the subject invention is shown at 11. The crawler track 11 on each side of the tractor 10 is carried on a front idler wheel 12, a rear driving sprocket 13 and on wheels 14 and 15. Idler wheel 12 is rotatively carried on the forward end of a lever 16. The other end of lever 16 strictivelyv pivoted about a horizontal axis disposed longitudinally of the tractor at the transverse center thereof. In the rearward portion of the tractor, the wheel 15 is rotatively carried on the forward end of a lever 17. The other end of the lever 17 rotatively supports the driving sprocket 13. The lever 17 is pivotally carried substantially at its center on the .final reduction gear housing of the tractor.

Each track 11 is made up of a number of basic units which are interconnected to form a continuous loop. Each basic unit of the track 11 comprises a pair of links 20 and 21, a track shoe 23, four nut and bolt arrangements 24, a bushing 25, a pin 26, and a pair of sealing rings 27.

The links 20 and 21 are mirror images of each other and are secured in parallel: spaced apart relationship to each other on the upper side of a track shoe 23 by the nut and bolt arrangements 24. The bushing 25 is firmly carried between the forward ends of a pair of links 20 and 21. The pin 26 is press-fit between the rearward ends of a pair of links 20 and 21 and is obviously rotatively carried through the bushing carried at the forward end of the adjacent pair of links. The sealing rings 27 are seated on an annular shoulder at each end of each bushing 25 and within an annular depression 32 in the track links 20 and 21.,The pin 26 of each basic track unit in extending through the bushing 25 of each adjacent basic track unit provides the pivotal connection between all of the basic track units to form a complete endless track.

Each link 20 and 21 is a generally longitudinal member having forward and rearward ends which are offset to lie on opposite sides of a plane including the contact surfaces of successive links. The contact surfaces of each successive pair of links 20 and 21 lie in vertical parallel planes. The forward end of each link 20 and 21 is provided with a hole 30 through which a bushing 25 ,is pressed in firm engagement. The rearward end of each link 20 and 21 is provided with a hole 31 to admit the end of a pin 26 in a tight press-fit therein. At the inside end of hole 31 is formed a counterbore 32 which as may be seen in FIG- URE 6 is adapted to receive the end portion of bushing 25. Each link 20 and 21 is further provided with an up, standing ear 33. The ears 33 keep the track on the wheels of the tractor. Such cooperation is shown in FIGURE with wheel 14. Each link 20 and 21 is further provided with an outwardly extending horizontal flange '34. The flanges 34 are provided with two holes therethrough to receive a pair of the nut and bolt arrangements 24.

Each of the track shoes 23 is roughly shaped as a rectangle with no openings therethroughother than those which are provided for the nut and bolt arrangements24. In the direction of tractor travel, which willhereafter be used to define the length of the shoe, each shoe 23 may be considered as divided into three sections, a forward section, a central section, and a rearward section. The upper side of the central section is substantially fiat and the underside thereof is provided with a transversely extending and depending grouser 36. The central section also carries openings therethrough on each side of the .grouser 36 for reception of the nut and bolt assemblies 24 for securing the shoes 23 to the underside of the links 20 and 21. As may be seen in the drawings, the central section is substantially shorter than the combined length of the forward and rearward sections of each track shoe.

The forward section of each shoe 23 is generally down- 1 wardly inclined relative to the plane of the central section. Each forward section is formed substantially as a portion of a cylinder the axis of which is concentric with holes 30-and 31, and the lower outside surf-ace of 'which provides a proper thickness reduced to a curved leading edge at 23a. The rearward section of each shoe 23 .is formed so that the underside is a convex curve which will cooperate with the upper surface of the forward section of an adjacent track shoe 23in a contiguous concentric relationship. The upper surface of the rearward section extends rearwardly in the plane of the upper surface of the central roller to a point directly below but not beyond a point directly below the center of pin 26, and then is formed to angle downwardly to the trailing edge of the rearward section. The length of the forward and rearward sections of the track shoes 23 are such that when two basic track units are positioned with the upper surfaces of the central sections lying in a common plane,

there is a substantial or approximately one-half overlap as shown at, 41 in FIGURE 3. In all of the foregoing.

pivotal positions of adjacent track units a substantially unbroken surface is presented to the earth beneath the track shoes. Importantly, this construction substantially prevents earth from working upwardly through the track shoes.

The relatively short pitch (distancebetween axes of ad-' jacent pins) together with the provided pivotal angles of approximately 18 permit very substantial reverse bends to the track when the crawler tractor passes over an obstruction such as is shown in FIGURE 1.

In a reduction to practice of the invention it has been found that the grousers 36 penetrated and left the earth with a minimum of disturbance. This is believed due to the fact that the. grousers in the above described construction lie in planes substantially midway between the axes of adjacent pins 26. Further, in the experimental operation of one reduction to practice it has been found that the track was unusually stable and provided an unusually quiet and comfortable ride for the operator. Although the reason for the stability is not known, it is suspected that the fact that the undersurface of each forward section of each track shoe 23 lies upon slightly compressed ground and thereby lends further support to the tractor at that position substantially midway between adjacent grousers is a condition which provides the re.- sulting stability.

The central and rearward sections of each track shoe 23 are further provided with a pair of flanges 42.. The flanges 42 are disposed along the side edges of the central and rearward sections and extend upwardly a distance roughly equal to the thickness of the track shoes 23. The flanges. 42 prevent earth from falling onto the upper surfaces of the track shries 23.

The further details of the construction of the track of the subject inventioninvolve the provisions made to seal the lubricated surfaces against the entrance of dirt or grit. The details of the sealing means are shown in FIG- URES 5 and 6. In FIGURE 6 the pin 26 and the link 20 have not been fully engaged. Upon complete engagement, the surfaces at 32a and25a are in contact. Because of the press-fit between the ends of the pins 26 and the rearward link sections, and the press-fit of the bushings 25 in the forward sections of the links, the pivotal contacting movement between adjacent basic track units occurs between the pins 26 and the inner surface of the bushings 25. To lubricate this contacting surface, one end of each pin 26 is provided with a recessed grease fitting 45. The grease fittings 45 communicate with the central outer surface of the pins 26 by means of lubricant passageways 46. The sealing rings 27 seal the lubricated surfaces against the entrance of dirt. As may be seen in FIGURE 6, each sealing ring 27 has a normal diameter which is slightly greater than the diameter of the annular shoulder of the bushing 25 upon which the sealing ring 27 is carried. The outer diameter of the sealing rings 27 substantially equal the diameter of the annular recessed opening 32 in the rearward link sections in which each sealing ring 27 is carried. Each sealing ring 27 further has a normal length which is greater than the length of the annular shoulder of each bushing 25 uponwhich the sealing ring 27 is carried. The end walls of each sealing ring 27 are provided with indented V-shaped surfaces which may be seen in FIGURE 6 in the normal condition. The V-shaped surfaces terminate in points at the inner annular surface of each sealing ring 27 and terminate in flat end surfaces at the outer annular surface of each ring 27. In FIGURES 5 and 6 it may be seen that the sealing ring 27 is carried on one end of a bushing 25 and within the counterbore 32 of a link 20 or 21. Thus it is clear that sealing is provided between bushing and link. When the bushings 25 and links 20 and 21 are projected together from a position such as shown in FIG- URE 6 to that shown in FIGURE 5, the sealing rings 27 are compressed endwise to substantially fill the annular space defined between the bushing ends and the links. The sharp, radially inward edges of each ring 27 provide oil sealing for the lubricant and the broader radially outer periphery of each ring 27 provides a seal against the entrance of dirt into the lubricated areas. A reduction to practice of the invention has shown that the above de scribed sealing arrangement provides excellent protection against the entrance of dirt into the lubricated areas.

Having described the invention, what is considered new and desired to be protected by Letters Patent is:

1. An endless track for an endless track vehicle comprising, a plurality of pairs of links pivotally interconnected to form a pair of transversely spaced apart endless loops, a plurality of track shoes, each of said track shoes comprising transversely extending forward, central and rearward sections, the central sections of each of said track shoes being secured to the underside of a pair of transversely spaced apart links of said endless loops, each of said forward sections being positioned to be inclined downwardly from the central section thereof, the upper surface of each of said forward sections and the underside of each of said rearward sections being curved so that said surfaces are in sliding engagement when adjacent interconnected links are pivoted, said surfaces of said sections of said track shoes further being substantially closed so that said endless track presents a substantially closed surface to any earth upon which said endless track vehicle is moved, wherein the degree of overlap between cooperating forward and rearward sections of adjacent track shoes is substantially one-half of each section when the adjacent central sections are in a common plane, the combined length of said forward and rearward sections being substantially greater than the length of said central section of each track shoe, whereby any intermediate portion of the length of said endless track is pivotable in both directions from a flat plane including the central sections thereof, each of said track shoes being provided with a transversely extending and depending grouser which is positioned centrally of and on the underside of said central section of each of said track shoes, and wherein the upper side marginal edges of each of said central and rearward sections of said track shoes are provided with upwardly extending flanges.

2. In an endless track as defined in claim 1, wherein adjacent pairs of track shoes are relatively pivotal through at least an angle of 17 in either direction from a flat plane including the central sections of said adjacent shoes.

References Cited UNITED STATES PATENTS 1,111,583 9/1914 Holt 305-11 1,148,518 8/1915 Krupp 305-11 1,289,408 12/ 1918 Davis 305-11 1,304,357 5/1919 Norelius 30554 1,333,175 3/1920 Johnson 30558 X 1,455,490 5/1923 Holt 305 2,699,974 1/ 1955 Deffenbaugh 305-11 2,743,140 4/ 1956 Bauer.

3,128,679 4/1964 Trendle 277 X LEO FRIAGLIA, Primary Examiner.

RICHARD J. JOHNSON, Examiner. 

1. AN ENDLESS TRACK FOR AN ENDLESS TRACK VEHICLE COMPRISING, A PLURALITY OF PAIR OF LINKS PIVOTALLY INTERCONNECTED TO FORM A PAIR OF TRANSVERSELY SPACED APART ENDLESS LOOPS, A PLURALITY OF TRACK SHOES, EACH OF SAID TRACK SHOES COMPRISING TRANSVERSELY EXTENDING FORWARD, CENTRAL AND REARWARD SECTIONS, THE CENTRAL SECTIONS OF EACH OF SAID TRACK SHOES BEING SECURED TO THE UNDERSIDE OF A PAIR OF TRANSVERSELY SPACED APART LINKS OF SAID ENDLESS LOOPS, EACH OF SAID FORWARD SECTIONS BEING POSITIONED TO BE INCLINED DOWNWARDLY FROM THE CENTRAL SECTION THEREOF, THE UPPER SIDE OF EACH OF SAID REARWARD SECTIONS AND THE UNDERSIDE OF EACH OF SAID REARWARD SECTIONS BEING CURVED SO THAT SAID SURFACES ARE IN SLIDING ENGAGEMENT WHEN ADJACENT INTERCONNECTED LINKS ARE PIVOTED, SAID SURFACES OF SAID SECTIONS OF SAID TRACK SHOES FURTHER BEING SUBSTANTIALLY CLOSED SO THAT SAID ENDLESS TRACK PRESENTS A SUBSTANTIALLY CLOSED SURFACE TO ANY EARTH UPON WHICH SAID ENDLESS TRACK VEHICLE IS MOVED, WHEREIN THE DEGREE OF OVERLAP BETWEEN COOPERATING FORWARD AND REARWARD SECTIONS OF ADJACENT TRACK SHOES IS SUBSTANTIALLY ONE-HALF OF EACH 